Re: [Qemu-devel] [PATCH v4 3/3] nvdimm: add 'unarmed' option

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Mon, Dec 11, 2017 at 03:28:06PM +0800, Haozhong Zhang wrote:
> Currently the only vNVDIMM backend can guarantee the guest write
> persistence is device DAX on Linux, because no host-side kernel cache
> is involved in the guest access to it. The approach to detect whether
> the backend is device DAX needs to access sysfs, which may not work
> with SELinux.
> 
> Instead, we add the 'unarmed' option to device 'nvdimm', so that users
> or management utils, which have enough knowledge about the backend,
> can control the unarmed flag in guest ACPI NFIT via this option. The
> guest Linux NVDIMM driver, for example, will mark the corresponding
> vNVDIMM device read-only if the unarmed flag in guest NFIT is set.
> 
> The default value of 'unarmed' option is 'off' in order to keep the
> backwards compatibility.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> ---
>  docs/nvdimm.txt         | 15 +++++++++++++++
>  hw/acpi/nvdimm.c        |  7 +++++++
>  hw/mem/nvdimm.c         | 26 ++++++++++++++++++++++++++
>  include/hw/mem/nvdimm.h |  9 +++++++++
>  4 files changed, 57 insertions(+)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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